/ Dictionary / Index O ortho-nitrophenol: Meaning and Definition of Find definitions for: or•tho-ni•tro•phe•nol Pronunciation: (ôr"thō-nī"tru-fē'nôl, -nol), [key] — n. See under(def. 2). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. orthomorphic projection orthonormal Related Content Daily Word Quiz: impetuous Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language